“He would have been capable for purposeful movement for a number of seconds.”

She told the court that adrenaline may have allowed him to carry on going and that it takes a few seconds for blood pressure to drop before a person collapses.

Essex Police are still looking for 18 year-old Bradley Blundell in connection with John Pordage's murder

A number of markings to Mr Pordage's left arm indicated blunt force trauma, with the doctor suggesting that a "linear-type" object may have caused injury.

Turning to the gunshot wound, Dr Fitzpatrick-Swallow explained how Mr Pordage's injury bore no signs of any soot or hot fumes from the gun, which would normally be used to indicate whether the bullet was fired at close range.

“From a pathology perspective, it’s of indeterminate range," she added.

"I can’t say whether it’s a couple of centimetres or a couple of feet."

The court heard how the bullet entered the left side of Mr Pordage's chest, travelled through his heart, the aorta and a lung before lodging into the chest wall.

It was also revealed that Mr Pordage suffered a “significant amount of blood loss,” with just over a litre of blood and clots being found in the left side of his chest.

During cross-examination by Bernard Richmond QC, representing the 16-year-old, Dr Fitzpatrick-Swallow explained how Mr Pordage had no injuries on his hands that had been caused by him landing punches.

But she did agree that one of his arm injuries was likely inflicted by "a slim object with some force".

A number of samples were sent away for toxicological examination, including hair, blood and urine.

Mr Pordage's mother gave an emotional plea for Bradley Blundell to come forward

These showed that Mr Pordage, who had driven to the garage in his white Peugeot van, was more than one-and-a-half times the legal drink drive limit and also had cocaine in his system.

Mr Richmond asked: “There was evidence that he had repeatedly and heavy use of cocaine?"

“Findings suggest there was repeated heavy use over the time span of the hair," replied Dr Fitzpatrick-Swallow

Tests also revealed Mr Pordage had both Trenbolone, a steroid, and testosterone in his system.

But the doctor confirmed that neither Mr Pordage's alcohol consumption or recreational cocaine use had any bearing on his death.